Django SlugField not unique - django

Question

I'm stuck from a couple hours and I can't solve this problem.
The following code works well, but if I write a "Title" that already exist I get:
UNIQUE constraint failed: appname_shopaccount.url_shop
Model
class ShopAccount(models.Model):
user = models.ForeignKey(User)
title = models.CharField(max_length=150)
url_shop = models.SlugField(max_length=200, unique=True)
company_name = models.CharField(max_length=200)
def save(self, *args, **kwargs):
self.url_shop = slugify(self.title)
super(ShopAccount, self).save(*args, **kwargs)
def __str__(self):
return self.title
Forms
class SignUpShopForm(ModelForm):
class Meta:
model = ShopAccount
fields=['title', 'company_name']
exclude= ('user',)
error_messages = {
'title': {
'required': "Enter a Shop name",
},
'company_name': {
'required': "Enter a Company name",
}
}
View
def signup_shop(request):
if request.POST:
form = SignUpShopForm(request.POST)
if form.is_valid():
account = form.save(commit=False)
account.user = request.user
account.save()
return HttpResponseRedirect('/account/updated/')
else:
form = SignUpShopForm(data=request.POST)
return render_to_response('register_shop.html', { 'form':form }, context_instance=RequestContext(request))
else:
return render_to_response('register_shop.html', context_instance=RequestContext(request))
How can I solve this problem?

Answer 1

Remove unique=True from the url_shop field in your model and update your database with python manage.py makemigrations and python manage.py migrate.
Be aware though that a slug field that can have non-unique values might have consequences for your app depending on how you are using it (two objects having the same url for example)

Answer 2

You can use unique_slugify to force a unique slug- https://djangosnippets.org/snippets/690/
import unique_slugify
class ShopAccount(models.Model):
...
def save(self, *args, **kwargs):
self.url_shop = unique_slugify(self, self.title, slug_field_name='url_shop')
super(ShopAccount, self).save(*args, **kwargs)
If the slug being created already exists, unique_slugify will append a '-1' (and on upwards) to the slug until a unique slug is found. Keep unique=True in your url_shop model kwargs :]
The reason you have an issue with your existing code is that slugify only converts the title field to a slug, not checking for existing slug values. With the method above, unique_slugify will check existing values and generate a slug that does not exist in the db yet.